Category Archives: Satellite images

Post navigation

I found this little press release that doesn’t have a huge amount of information, but is interesting nevertheless. The Coordinating Committee for Prediction of Volcanic Eruptions of Japan (nice name) is putting seven volcanoes on “24/7” monitoring. That sounds like we might see a lot of eruptions in Japan soon … except that their rationale was that these volcanoes “are likely to affect public life by erupting or becoming active in the coming 100 years”. That is quite the window of eruptive opportunity! The question is what exactly “24/7” monitoring – does this mean that someone/something will watch seismicity for signs of activity, or will this be a dedicated position that coordinates seismic, gas and deformation monitoring? The article doesn’t say much beyond seismographs and (vaguely) GPS. Nor does it mention what the seven new volcanoes are beyond Mt. Shirane and Mt. Norikura. However, I do give Japan credit for having such foresight when it comes to potential volcanic hazards.
One volcano that is already being constantly monitored is Mt. Asama, which has been erupting for over week. However, folks are already wondering when officials will say that Asama is “back to normal”. You can get a good idea of the ash dispersal from Asama with this excellent satellite image (above) from just after the January 21, 2009 eruption.

The NASA Earth Observatory website posted this great image of Redoubt taken from Landsat images in 2000.
You can see a few neat things. The main thing I notice is that the Drift River Oil Terminal is in about the worst place you could put an oil terminal near a volcano like Redoubt. All the material from recent eruptions at Redoubt get focused down into the Drift River, which then heads off into the Cook Inlet via the Drift River flood plain (upper right hand side of the image). When this image was taken, the Drift River is still grey with volcanigenic material even 10 years after the last activity, showing that most of the material is mobilized in that direction. It still amazes me that the oil terminal was ever allowed to be built in that location.
As for the current state of things at Redoubt, AVO reports that the seismicity is still going and things remain much the same as it has been for the past few weeks. Officials on the Kenai Peninsula are assuring residents that they’re ready for an eruption. At this pace, they might have months to prepare!

It is hard to believe that the eruption at seem to come out of nowhere at Chaiten started over 8 months ago now, and apparently is still not showing many signs of abating. I did get a chance to see some great talks and posters at AGU last month about the Chaiten eruption, with the key points I took away being that Chaiten is erupting a very crystal poor rhyolite (<1% crystals) and that it seems that the source of the magma is relatively deep in the Andean crust. Also, there are some indications that the eruption at Chaiten may have been tectonically instigated – i.e., that earthquakes in the area might have helped the magma to erupt – at least that is what Luis Lara of the SERNAGEOMIN believes (hat tip to Thomas Donlon for the link). The eruption at Chaiten also wreaked more havoc on aviation in South America than we thought, effecting airports 1000s of kilometers away and almost bringing down a number of aircraft. Most everyone I talked to seems to think what we are seeing is very similar to what happened at Little Glass Mountain in California about 1,000 years ago.
Moreover, the eruption hasn’t really stopped since it began in May of 2008. In fact, just last week we saw a collapse of part of the new dome that have produced some pyroclastic flows within and outside the caldera (see above and the Volcanism Blog) and fed more ash into the choked rivers near the volcano. It is anyone’s guess (well, at least at AGU) how long this eruption might go on – weeks? months? years? – but the consensus is that this might be a once-in-a-lifetime eruption (but we already knew that, didn’t we?)

The latest eruption of Sourfriere was captured from space, and NASA has just released the MODIS picture of the volcano in action. The image (above and linked) was taken 2 days after the first explosion of this unanticipated and unexpected eruption – December 4. You definitely get the idea of how much of the island of Montserrat is taken up by the volcano itself (pretty much all of it). Not much else to report on Soufriere Hills beyond the update from MVO (via SI/USGS) for the end of last week:

On 3, 4, and 5 December small, relatively slow moving pyroclastic flows traveled no more than 3.2 km down the Gages valley. In periods between the events, near-continuous emissions of ash-laden steam were noted. The Hazard Level remained at 3.

So, beyond the lack of any precursory activity, sounds like eruption-as-usual on Montserrat.

So, I get a steady diet of email messages here at the Eruptions HQ, so I thought I could try a little roundup of the great information/links that you readers are sending (and I apologize for taking so long for some of these). Enjoy!
– Tim Stone tells us about GeoEye pictures of volcanoes. GeoEye is the new satellite launched to add to the Google Earth images of the planet. There are some quite striking images of volcanoes included in the collection.
– Richard Roscoe sends us to some updated images of the on-going volcanic activity on Montserrat. As usual, there is an abundance of excellent images and information on this Photovolcanica page.
– Dan Cerveny points us to the preview of a new TV show that talks about the current eruption at Chaiten in Chile. In Harm’s Way(on the CW) is about dangerous professions (volcanologists are always assured of a place on that list) and episode 106 featured John Seach quest for pieces of the volcano. Not sure when it might air again, but I’m sure it will pop up on reruns (or online).
Keep the emails coming!

El Reventador, the composite volcano in Ecuador, has been producing explosions and ash for the last few days, so says reports from the country’s Geophysics Institute. El Reventador is only 100 km from Ecuador’s capitol, Quito, and in 2002 the volcano blanketed much of the city in ash. However, the eruptions currently occurring are much smaller and limited in scope, producing ash and throwing incandescent blocks out near the vent (see above). No evacuations are currently planned. These types of eruptions are typical for El Reventador since 2002, with increased activity every few years producing ash fall, lava flows and pyroclastic flows. Prior to that, the volcano has been quiet since 1976.

Sorry about the dearth of posts. It has been a busy week here in Davis and I’ve been a little distracted by the upcoming election. Combined with the relative lack of volcano news this week, the posting has been lackluster.
However, that being said, I will try to make up for some of it by starting my Volcano Profiles series that will bide the time between volcano news. I start with a volcano that was suggested by Eruptions reader Thomas Donlon: Rabaul.

VOLCANO PROFILE: RABAUL

Location: Papau New Guinea

Height: 688 m

Geophysical location: Boundary of Australian plate and Pacific plate, where the Pacific plate is subducting under the Australia (note: very simplified as there are a number of microplates involved as well).

Summary: Rabaul is an 8×14 km caldera that has been partially filled by the sea, but multiple peripheral vents can been seen along the caldera edges. Likely the caldera seen today was formed 1,400 years ago and there is evidence that an ancestral caldera formed 7,100 years ago. The volcanic system erupts basaltic through dacitic lavas from these vents, producing lava flows and voluminous pyroclastic flows that have caused extensive death and damage to the settlements near the caldera over the last 200 years. The currently active vents are Tavurvur and Vulcan.

Current status: The Rabaul caldera is currently in an active cycle which started in 1994, producing ash and steam eruptions, along with lava flows and ash flows from both Tavurvur and Vulcan. The caldera has been constantly active since 2006, with the most recent activity consisting of earthquake and small, conduit-clearing eruptions from a shallow reservoir.

Notable Recent Eruptions: The Rabaul Caldera has had two major eruptions in the past 100 years and they are stark contrasts in terms of hazard mitigation and evacuation. The eruptions from Vulcan and Tavurvur in 1937 killed more than 500 people while blanketing the countryside in ash. It also produced a tsunami that washed boats onshore. This eruption is thought to have been roughly a VEI 4. Vulcan and Tavurvur followed up this eruption with another VEI ~4 in 1994, but thanks to excellent planning, evacuating practice and an organized response, the death toll to this eruption was a mere 5 (an excellent summary of this evacuation was presented on an episode of NOVA). This eruption produced ash fall and pyroclastic flows from at least 5 vents along the caldera and the ash fall effects were amplified by heavy rain (likely caused by the eruption itself). Some of this ash was in excess of 7 feet and destroyed 80% of the structures in the town of Rabaul. Interestingly, the only real signs of a potential eruption at the Rabaul Caldera before 1994 was significant surface uplift in the caldera in the mid-1980s, followed by quiescence until the 1994 eruption.

On Sunday afternoon, a large ash eruption occurred at Halemaumau Caldera at Kilauea. Not only did the volcano belch more grey ash than usual, but also red-hot incandescent material can be clearly seen being thrown from the vent during the vigorous eruption. The coolest thing about the eruption is that it was all caught on film by the USGS/HVO. Take a look (at three times speed) – this video is from the morning of October 12, but there are a series of video from the whole weekend on the website.

I wanted to post the new MODIS image of Chaiten that caught the volcano erupting on September 3. I won’t go into too much details, there are a lot of great updates over on the Volcanism Blog, but needless to say, the volcano is still very active, producing tall ash columns (you can see the ash blanket around the volcano in the image above as the plume drifts off to the northwest), earthquakes and pyroclastic flows as the dome in the caldera continues to grow. I’ll be interested to see what geologists know about the eruption and volcano when the AGU meeting rolls around in December as there will be a special session on the Chaiten 2008 eruption.

This article sums up a lot of the events that led up to the Kasatochi (Alaska) eruption last week from the point of view of the biologists on the island itself right before it erupted. There are some great descriptions of the whole island shaking for 10 minutes, and they also offer some exciting new details such as this:

“Jeff Williams, a biologist for the maritime refuge, sailed by the island on the refuge boat the Tiglax and said the island has a new shape; what were steep cliffs rising from the ocean on the island’s east and west sides now appear to be long, gradual slopes.”

That would imply to me that the eruption has produced a lot of pyroclastic material that now lies as an apron of material around the vent – much like a river delta or alluvial fan of volcanic material. Most likely, this material will be quickly eroded if it is merely piles of loosely consolidated pumice and ash, but at least for the time being, Kasatochi has added some valuable oceanside real estate to the island.